tbuckley/cabot-search huggingface dataset:
CTIM-30. THE PRIVATE AND RECURRING ANTIGENIC PROFILE OF HUMAN MEDULLOBLASTOMA
Authors: Changlin Yang, Vrunda Trivedi, Duane Mitchell
Journal: Neuro-Oncology (2022)

Abstract BACKGROUND Identifying tumor rejection antigens remains a major barrier to developing effective immunotherapeutics and their application to pediatric brain tumors. We performed a multi-faceted computer algorithm, the Open Reading Frame Antigen Network (O.R.A.N.), on medulloblastoma transcription profiles and predicted antigens across a broad array of antigen classes. METHODS Patient-specific HLA haplotypes were called via customized Optitype and Phlat algorithms. Only expressed mutations such as single nucleotide variations, small indels, gene fusions, and Tumor Associated Antigens (TAAs) were used for antigenic epitope predictions. TAAs were selected only if expressed &amp;gt; 1 transcript per million (TPM) in tumor and the standardized expression across a human tissue database. Immunogenic TAA epitopes were screened against a customized human proteomic library to guarantee that epitopes were not shared by other expressed isoforms or genes. Immune deconvolution with single cell RNASeq integration was leveraged for teasing out medulloblastoma immunologic landscape. RESULTS We hypothesized that medulloblastomas are immunologically heterogeneous and express genes with limited normal tissue expression that may serve as targets for immunotherapy. In this study, most neoantigens from medulloblastoma patients were found private suggesting a personalized neoantigen based therapy was on demand. In addition, recurring neoantigens were common in SHH but composed only a small proportion of putative antigens in WNT, Group 3 and Group 4 patients. However, recurring TAAs were found to be more commonly expressed in the latter three molecular subgroups but not in SHH. Together, combining personalized neoantigen vaccine and taking advantage of recurring TAAs approach may maximize anti medulloblastoma effect. CONCULSION Medulloblastoma is a heterogeneous disease, and the current standard of care treatments don’t take that into account. Newer, and safer, patient-specific treatment approaches are required to treat high-risk patients who are not cured by the standard therapies .Cellular immunotherapy might be key to improving survival and avoiding morbidity.
ANGI-10. IMPLICATIONS OF EPITHELIAL MEMBRANE PROTEIN-2 (EMP2) IN THE PATHOGENESIS OF MENINGIOMAS
Authors: Khashayar Mozaffari, Brian Aguirre, Anubhav Chandla, Madhuri Wadehra, Isaac Yang
Journal: Neuro-Oncology (2022)

Abstract INTRODUCTION VEGF-A is an important mediator of angiogenesis in meningiomas. However, targeting this protein with bevacizumab has offered only a modest improvement in survival, suggesting that there are other compensatory mechanisms involved, enabling vascularization despite ongoing treatment. Epithelial membrane protein 2 (EMP2), a cell surface protein, promotes angiogenic processes in gynecological cancers and brain tumors including gliomas and glioblastoma. However, little is known about its etiology and mechanism of action within meningiomas. OBJECTIVE We aimed to evaluate EMP2 expression in non-pathologic brain tissue, tumor specimens, and in meningioma cell lines. We also aimed to understand its mechanism within cells with regard to proliferation and invasion. METHODS Non-pathologic brain tissues from routine autopsies and tumor specimens from surgical resection were analyzed. Additionally, four meningioma cell lines were obtained (CH157, BEN-MEN1, SF1335 and IOMM-LEE) and changes in cellular proliferation and invasion were measured. Furthermore, EMP2 expression was modulated using lentiviral infection. A p-value &amp;lt; 0.05 was considered statistically significant. RESULTS EMP2 mRNA and protein expression were significantly higher in the meningioma specimens compared to non-pathologic meninges. Its expression also positively correlated with an angiomatous pattern and VEGF-A mRNA expression. In vitro, high EMP2 protein expression was noted in all cell lines, and quantification demonstrated highest expression in the malignant cell line, the IOMM-LEE. Viral vectors were subsequently utilized to create EMP2 overexpressing and knockdown IOMM-LEE models. Western analysis demonstrated a correlation between EMP2 overexpression and HIF1α, a key mediator of tumor growth and angiogenesis. CONCLUSION Our data from primary tumor samples and in vitro models implicate EMP2 in meningioma pathogenesis. This warrants further investigation by evaluating the effects of anti-EMP2 therapy on tumor growth and invasiveness in both in vitro andin vivo models.
DDEL-16. DELIVERY OF OT-101 - TGF-Β ANTISENSE- FOR THE TREATMENT OF GLIOBLASTOMA
Authors: Vuong Trieu
Journal: Neuro-Oncology (2022)

Abstract OT-101 - a TGF-beta antisense- is active against recurrent glioblastoma in G004- a phase 2 clinical trial [Uckun FM, Qazi S, Hwang L, Trieu VN. Recurrent or refractory high grade gliomas treated by convection enhanced delivery of a TGF-beta2 targeting RNA therapeutic: a post-hoc analysis with long-term follow up. Cancers. 2019, 11:1892]. OT-101 was delivered intratumorally by Convection Enhanced Delivery (CED). To further expand the application of OT-101, we explored the intrathecal delivery of tritiated OT-101 into Sprague-Dawley CD (albino) rats. Throughout the studies, there were no sex differences. After 1 hr intracerebral infusion in rats, OT-101 was limited to the infusion site. Whereas for the 1 hr itravesicular infusion, OT-101 was more widespread with 35X, 19X, 12X higher concentration found in cerebellum, remaining cerebrum, cerebrospinal fluid (CSF), respectively. OT-101 concentration was stable for the first 4 hours post infusion and decayed biexponentially with a slow terminal half life for tissue but not for CSF, suggestive of rapid penetration of the underlying tissue away from the CSF compartment. Minimum amount of OT-101 was detected in the plasma compartment. Intrathecal bolus administration of 0.1mL of OT-101 at 14, 30, 200, 300, and 500 uM into cynomolgus monkies did not result in any single dose toxicity. Histopathology examination revealed no substance-related histomorphological lesions in the cavum subarachnoideale of the lumbar region. No changes were noted in the grey and white matter of the spinal cord, the nerve trunk, and nerve cells did not show any abnormalities. These data suggest that intrathecal administration of OT-101 is a potentially effective delivery route for antisense therapeutics such as OT-101 to the midline ie. for Diffuse Midline Glioma (DMG). A phase 1b/2 clinical trial evaluating OT-101 against DMG is proposed and the trial design will be presented
NIMG-39. AMINO ACID PET-MRI OF HIGH-GRADE GLIOMA
Authors: Maciej Harat, Józefina Rakowska, Marek Harat, Tadeusz Szylberg, Jacek Furtak, Izabela Miechowicz, Bogdan Małkowski
Journal: Neuro-Oncology (2022)

Abstract OBJECTIVE MRI is gold standard for the diagnosis, surgery and radiation therapy of patients with high-grade glioma. Amino acid PET is useful in gliomas without contrast enhancement in MRI but it is unknown whether PET better identifies high-grade foci than T1-sequence with contrast enhancement or improve definition of high grade glioma infiltration related to T2/Flair images. METHODS More than 400 biopsy specimens from twenty-three patients with suspected high-grade glioma were examined in this prospective study. Patients meeting the inclusion criteria were referred for hybrid 18F-FET-PET-MRI before stereotactic biopsy. Biopsies were planned based on early FET-PET acquisition 5-15 minutes post injection and MRI. The following biopsy sites were determined in each case: (i) site of contrast enhancement and increased FET uptake; (ii) contrast enhancement but no increase in FET uptake; (iii) increased FET uptake but without contrast enhancement; and (iv) peripheral areas hyperintense in T2 FLAIR without increased FET uptake and contrast enhancement. RESULTS In 35% cases, the biopsy result was changed to a higher tumor grade after the inclusion of FET-positive sites. In all cases, high FET uptake was visualized and confirmed outside areas of contrast enhancement on MRI, indicative of high-grade glioma. Results from biopsies based on the FLAIR sequences corresponded to neoplastic lesions in 13 cases (57%), most often with a lower grade than in areas of high FET uptake. CONCLUSIONS FET-PET can be used to locate the most malignant areas of contrast-enhancing gliomas and impact the biopsy results. Surgery or radiotherapy planned solely on MRI images may miss parts of tumor presenting highest malignancy. Brain areas hyperintense in T2 FLAIR without increased amino acid uptake are not specific for malignancy in high grade gliomas.
EPID-21. INCORPORATING RECEIPT OF STANDARD-OF-CARE AS A KEY VARIABLE IN POPULATION-BASED STUDY OF GLIOBLASTOMA SURVIVAL
Authors: Ping Zhu, Clark Chen
Journal: Neuro-Oncology (2022)

Abstract Object Populational database research with real-world settings offers epidemiologic insight at scales that cannot be easily recapitulated, especially for rare cancers such as glioblastoma. However, most survival studies were conducted without consideration for whether the patients received the standard of care (SOC). METHODS Survival analysis was performed using the National Cancer Database (NCDB) and stratified for Methyl-guanine-methyl transferase (MGMT) promotor methylation. Glioblastoma patients age &amp;lt; 40 were excluded to minimize the prognostic impact of isocitrate dehydrogenase (IDH) mutations. SOC was defined as the receipt of chemotherapy and radiation within 2-6 weeks of surgical biopsy or resection. Sensitivity analyses were performed allowing chemotherapy and radiation start date to differ by 0, 3, 5, and 10 days. RESULTS Within the NCDB (N = 11231), 54.7% of newly diagnosed glioblastoma patients did not receive SOC. The median survival time (MST) estimates were significantly shorter for all glioblastoma patients (10.9, IQR: 4.3-21.5, months) relative to SOC treated patients (15.3, IQR: 8.6-26.2, months; p &amp;lt; 0.001). The MST estimates remain stable in sensitivity analysis allowing for 0, 3, 5, and 10-day discrepancy between chemotherapy and radiation start date. These results were recapitulated using the SEER-Medicare database. The MST estimates for MGMT methylated and unmethylated glioblastoma patients after SOC in the NCDB were 21.0 and 14.5-mo, respectively. The overall and MGMT-specific survival estimates mirror those reported by the SOC arms of five recent randomized controlled studies. Analysis of all glioblastoma patients indicates survival benefit of immunotherapy (HR: 0.90, p = 0.020) while such benefit was absent in SOC treated patients (HR: 0.97, p = 0.644) - with the latter observation more reflective with trial results and clinical experiences. CONCLUSION Survival analysis in the populational database study can be misleading without information on the receipt of SOC.
EXTH-64. IPSC-DERIVED NK CELLS EXHIBIT POTENT IN VITRO AND IN VIVO TUMORCIDAL ACTIVITY AGAINST PATIENT-DERIVED GLIOBLASTOMA STEM CELLS (GSCS)
Authors: Jianfang Ning, Zachary Davis, Frank Cichocki, Hongbo Wang, Katie Tuininga, Ryan Bjordahl, Tom Lee, Jeffrey Miller, Clark Chen
Journal: Neuro-Oncology (2022)

Abstract INTRODUCTION Natural Killer (NK) cells play pivotal roles in cancer immune surveillance and harbor potent anti-tumor activities. We have engineered an induced pluripotent stem cells (iPSCs) derived, NK cell (termed FT538) that express 1) a high-affinity non-cleavable CD16 Fc receptor to facilitate antibody engagement, 2) a membrane-bound IL-15/IL-15 receptor fusion to enhance NK activity and persistence and 3) a knock-out of CD38 to enhance NK metabolic fitness. FT538 is produced in a GMP-compliant manner as an off-the-shelf immunotherapy. Clinical experiences with FT538 have shown evidence of durable anti-tumor immunity after single administration in select lymphoma patients. METHODS We performed pre-clinical studies to characterize the tumoricidal activity of FT573 against glioblastomas. RESULTS Without specific antibody to engage CD16, FT538 exhibited potent in vitro activity against ~80% of a panel of isocitrate dehydrogenase wild-type patient-derived xenograft (PDX) glioblastoma lines, including MGG8. When directly injected into the murine brain, 50% of the FT538 persisted for &amp;gt; 2 weeks without addition of exogenous cytokine. Moreover, the mice exhibited no evidence of neurologic compromise, and brains harvested after injection show no signs of FT538 activation. In vivo intratumoral injection of FT538 into an orthotopically established MGG8 glioblastoma caused a ~20 fold increase in granzyme B release by FT538, with a comparable increase of cleaved-caspase 3 in the tumor. In independent experiments, &amp;gt; 90% of mice orthotopically implanted MGG8 survived beyond 100 days after intra-tumoral FT538 while all mice treated with mock injection died by 60 days. For glioblastoma PDX refractory to FT538, such as MGG4, tumoricidal activity of FT583 can be induced in vitro and in vivo by the addition of a tri-specific engager targeting B7H3, a surface protein highly expressed in glioblastomas. CONCLUSION Our results demonstrate great promise of FT538 as a glioblastoma therapy, with plans for translation into a first-in-human clinical trial.
CSIG-10. PHARMACO-PHOSPHO-PROTEO-GENOMICS OF PEDIATRIC HIGH-GRADE GLIOMAS – A PILOT STUDY
Authors: Izac Findlay, Dilana Staudt, Padraic Kearney, Holly McEwen, Ryan Duchatel, Evangeline Jackson, Tyrone Beitaki, Nathan Smith, Nicholas Vitanza, Ron Firestein, Jason Cain, Sabine Mueller, Eddy Pasquier, Carl Koschmann, Esther Hulleman, Javad Nazarian, Mitchell Hansen, Frank Alvaro, Melissa Davis, Sebastian Waszak, Matthew Dun
Journal: Neuro-Oncology (2022)

Abstract Pediatric high-grade gliomas (pHGG) are the leading cause of cancer-related death in children and young adults. Current treatment strategies are centered on maximal safe resection, followed by radiotherapy, and interrogation of the tumor genome to identify targetable mutations. Unfortunately, we are yet to see an improvement in patient outcomes with a median overall survival remaining 15-months. To improve patient outcomes, we have begun to characterize the genome, proteome, and phosphoproteome of 168 pHGGs to better understand the functional consequences of their somatic alterations as well as their influence of the tumor microenvironment. Employing a novel ‘pharmaco-phospho-proteo-genomics’ pipeline, we have analyzed pHGG cell lines and tumor tissue specimens at diagnosis, relapse (partial resection congenital glioblastoma), and autopsy. Genomic profiling was conducted utilizing the 523-gene TruSight Oncology 500 (TSO500) next-generation sequencing panel. Simultaneously, tumor proteomes and phosphoproteomes were characterized using our high-throughput global phospho-proteomic profiling technique termed pHASED (phospho Heavy-labelled-spiketide FAIMS StEpped-CV DDA). High-fidelity tumor proteomic and phospho-proteomic data were identified and compared to normal control brain samples. Across 40 pHGG samples, we identified 290 unique somatic alterations with a high predicted impact severity and quantified 7,345 unique proteins and 3,327 phosphoproteins. Gene panel sequencing of a critical pediatric glioblastoma patient sample identified 18 somatic alterations, eight of which had a high predicted impact severity, however, none were targetable. Conversely, phosphoproteomic profiling identified enriched MAPK and PRKCB signaling, relative to normal brain tissues, thereby encouraging the use of the TGA/FDA approved therapies trametinib (MAPKs) and enzastaurin (PRKCB). In vitro investigations confirmed the utility of these treatment approaches and in vivo patient derives xenograft mouse models for this sample are under investigation. This pilot study provides critical data to support the benefit of interrogating the genome, proteome, and phospho-proteome of these devastating tumours to aid in the selection/development of effective treatment strategies.
CTIM-22. THE COMBINATION OF LOMUSTINE AND THE IMMUNOCYTOKINE L19TNF IS A PROMISING TREATMENT FOR RECURRENT GLIOBLASTOMA
Authors: Thomas Look, Emanuele Puca, Riccardo Stucchi, Roberto De Luca, Patrick Roth, Dario Neri, Michael Weller, Teresa Hemmerle, Tobias Weiss
Journal: Neuro-Oncology (2022)

Abstract Glioblastoma is the most aggressive primary brain tumor and adults and poorly immunogenic. Treatment options for recurrent glioblastoma after standard of care chemoradiation are limited Several immunotherapeutic strategies including peptide vaccination and immune checkpoint inhibition have so far failed to improve survival and except from potentially regorafenib, no other agent has demonstrated superior activity to lomustine. Therefore, there is an urgent need for more effective treatment strategies for recurrent glioblastoma. Here, we investigate a new treatment combination based on the alkylating chemotherapy lomustine and the tumor-stroma targeting antibody-cytokine fusion protein L19TNF in preclinical glioma models and patients with recurrent glioblastoma. The combination treatment with lomustine and L19TNF demonstrated strong synergistic anti-tumor activity in several immunocompetent orthotopic glioma models curing the majority of tumor-bearing mice, whereas other mono- or combination therapies for example with anti-PD1 had only limited anti-glioma activity. Investigations of the mechanism of action revealed that lomustine plus L19TNF led to intratumoral necrosis, DNA damage and triggered a strong local anti-tumor immune response with increased MHC-I expression, presentation of neoepitopes and increased abundance of tumor-infiltrating lymphoid cells. In the first patients treated within a phase I/II clinical trial (NCT04573192), the treatment was well tolerated, and durable objective tumor responses and disease stabilizations could be observed also in patients with an unmethylated MGMT promoter.
INNV-15. MANAGEMENT AND LONG-TERM OUTCOMES OF ADULTS WITH MEDULLOBLASTOMA
Authors: Bryan Neth, Aditya Raghunathan, Sani Kizilbash, Joon Uhm, William Breen, Derek Johnson, David Daniels, Ugur Sener, Ivan Carabenciov, Jian Campian, Anita Mahajan, Michael Ruff
Journal: Neuro-Oncology (2022)

Abstract INTRODUCTION Medulloblastomas (MB) are embryonal tumors arising in the cerebellum, predominantly affecting pediatric patients. Recognition of molecularly defined subgroups has advanced management. Factors influencing the prognosis and management of adult MB patients remain poorly understood. METHODS We retrospectively reviewed our experience with adult (&amp;gt; 18 years at initial diagnosis) MB patients, diagnosed between 1992-2020. Molecular subtyping corresponding to the 2021 WHO Classification was performed. Kaplan-Meier estimates (Log-rank test assessing for group differences) were performed for univariate survival analysis with cox regression used for multivariate (subgroup, age, gender, disseminated disease, extent of resection) analyses. RESULTS Our cohort included 76 adult MB patients (62% male), with a median age of 31.7 years (range: 18-66) at diagnosis, and median follow-up of 7.7 years (range: 0.6-26.9). 58 patients had sufficient tissue for molecular characterization by immunohistochemistry and corresponded to the SHH-activated (n=37; 64%), non-WNT/non-SHH (n=12; 21%), WNT-activated (n=9; 15%) subgroups. At initial diagnosis, all patients underwent radiotherapy, with 97% (n=66) receiving craniospinal irradiation with a boost either to the posterior fossa (75%) or tumor bed (22%); and underwent gross total resection (n=51; 67%) and chemotherapy (n=56; 75%). Median overall survival (OS) for the whole cohort was 14.8 years (93% 2-year OS; 86% 5-year OS; 64% 10-year OS) and was longer for younger patients (&amp;lt; 30: &amp;gt; 15.4 years, &amp;gt; 30: 9.9 years; Log-rank p&amp;lt; 0.001). No significant OS difference was identified by MB molecular subgroup (SHH, TP53-wt: 14 years, WNT: 11.4 years, non-WNT/non-SHH: &amp;gt; 14.8 years; Log-rank p=0.1167) or extent of resection. Only age at diagnosis remained significant in multivariate survival analyses. DISCUSSION We report one of the largest retrospective cohorts in adult MB patients with molecular subtyping. Survival and molecular subgroup frequencies were similar to previous reports. Survival was longer for younger patients and was not significantly different by MB molecular subgroup or extent of resection.
CCRG-02. THE DIFFUSE MIDLINE GLIOMA MUTATIONS, H3.3 K27M AND G34R/V, INHIBIT MITOTIC PHOSPHORYLATION OF SERINE 31, LEADING TO TUMOR FORMATION THROUGH INCREASED CHROMOSOMAL INSTABILITY
Authors: Charles Day, Florina Grigore, Alyssa Langfald, Faruck Hakkim, David Daniels, Kevin Vaughan, James Robinson, Edward Hincliffe
Journal: Neuro-Oncology (2022)

Abstract Diffuse midline gliomas (DMG) are high-grade pediatric gliomas that frequently harbor heterozygous histone H3.3 K27M, G34R, or G34V mutations. These mutations alter histone methylations, although the precise mechanism(s) of gliomagenesis remains uncertain. H3.3 contains a unique Serine at position 31 that is phosphorylated in prophase and dephosphorylated in anaphase during normal cell division. In an aberrant division, chromosome missegregation triggers S31 phosphorylation along chromosome arms in anaphase leading to p53-induced cell cycle arrest. Here we show in vitro and in vivo, that H3.3 K27M, G34R, and G34V significantly suppress S31 phosphorylation by Chk1 (the mitotic S31 kinase). In diploid cells, overexpression of H3.3 K27M, G34R, G34V, or non-phosphorylatable S31A significantly increases the frequency of chromosome missegregation, while H3.3 K36M did not. This missegregation phenotype could be rescued by overexpression of K27M/S31E or G34R/S31E double mutants. Next, we used genome editing to revert K27M or G34V patient-derived DMG cells to WT or replace the mutant allele with S31A. Reversion to WT increased metaphase S31 phosphorylation and reduced chromosome missegregations, but inserting an S31A mutation caused more mitotic defects. Following a mitotic error, newly formed aneuploid cells overexpressing K27M, G34R, or G34V suppress p53 levels and continue to divide, while WT overexpressing cells always arrest. To test the effects of diminished S31 phosphorylation on gliomagenesis, we utilized a novel mouse model of DMG. Expression of PDGFβ linked to H3.3K27M, H3.3G34R, and H3.3S31A in neural stem cells in vivo promoted the development of high-grade gliomas in under 100 days, whereas PDGFβ-H3.3WT did not. Notably, the S31A tumors had histologically normal levels of K27me3 and K36me3. This work shows that a single DMG-associated point mutation in H3.3 can generate chromosomal instability and suggests that chromosomal instability is a major contributing factor to DMG K27-altered and DMG G34-altered tumor formation.